Motion Tracking

1
Motion Tracking Position Acquisition

• Final Presentation

Solomon Gates William K. Grefe Jay Michael
Heidbreder Jeremy Kolpak
2
Overview of Project Objective

• Primary Goal
• Achieve accurate and precise motion of laser
  pointer directed at a locator beacon
• Secondary Goal
• Obtain precise object position from sensor input

3
Original Design Specifications

• Object tracking velocity
• Object velocity of 10 mph
• Pan/Tilt velocity of 10 radians per second
• Object acquisition within 1 second
• Distance to object ½ft 20ft
• Range of motion
• Pan range of 180
• Tilt range of 90
• Target Acquisition Accuracy
• ½ at a range of 20 ft (0.0021 radians)
• 1/8 at a range of 6 (.021 radians)
• Tracking Moving Object
• 1 _at_ 20 ft (0.004 radians)
• ¼ _at_ 6 (0.041 radians)

4
Controller Design Process
Simulate Desired Motors
Simulate Plant (Linearized System)
Designed PID Controllers
Tested System (Real World)
Designed Friction Compensation
5
Designing a Suitable Controller

• Linearized our simulated plant system
• Estimated desired dampening and natural frequency
  values to achieve a suitable overshoot and
  settling time.
• Created a PID controller
• Simulated the PID controller input response with
  the linearized plant system.

6
Real World Plant/Controller Testing

• Initially our real world system did not react to
  the controller as the simulated system.
• Real World friction compensation was initially
  non-existant (identify viscous and coulomb
  friction)
• Simulated plant friction model was incorrect
• Estimated system models were not completely
  accurate causing phase difference in system
  response

7
Pan Comparison
8
Pan Comparison
9
Tilt Comparison
10
Tilt Comparison
11
Basic Friction Compensation System

• Add coulomb compensation based on the change in
  encoder reading
• This type of compensation can fail when the motor
  approaches the steady state value (stiction zone)
• If at this point the encoder reading does not
  change, the coulomb compensation is not added and
  the motor does not move and for future readings
  the encoder will not change.
• Basic Friction Point to Point Video

12
Group 3 Friction Compensation System

• Add coulomb compensation based on the difference
  between the current and desired position.
• This will provide constant compensation until the
  controller acquires the desired position.
• This can however cause oscillations for small
  movement and near the steady state value.
• We fixed this by adding a dead zone to remove
  oscillations near steady state.

13
Pan Point to Point Accuracy(Point to Point Video)
14
Tilt Point to Point Accuracy
15
Pan Motion Testing(Show Motion Tracking Video)
16
Pan Motion Testing (Zoom)
17
Tilt Motion Testing
18
Tilt Motion Testing (Zoom)
19
Sensor Design

• Beacon will be built from six ultrasonic
  transceivers to allow 360 range
• Three receivers received signal

20
Sensor Problems

• Radio frequency transmitter and receiver pair
  proved too complicated to implement on ARCS
  system
• Ultrasonic transmitter and receivers were built
  and tested devices shown to communicate with
  each other
• No time remained to integrate transmitter with
  PIC microcontroller and MATLAB code with enough
  accuracy.

21
Position Acquisition

• Receivers built and tested to acquire a signal
  from the transmitter
• MATLAB code used to calculate x,y,z position
  based upon simulated distance information from
  three simulated receivers
• Position was then related to the given position
  of laser to generate angle values

Da, Db, Dc
x, y, z
T1, T2
MATLAB Triangulation Routine
MATLAB Angle Localization Routine
Controller
22
Performance Comparison
23
Success Challenges

• It was challenging to relate the real world plant
  to the simulated model. We were able to achieve
  this in the end.
• Creating the friction compensation was more of a
  challenge than we had expected, and in the end
  came up with a new way to handle this. This new
  system however, had its own drawbacks that we
  overcame.
• Creating a sensor system from scratch. We were
  able to successfully create the components
  however time did not permit us to integrate and
  test them with our controller.